Biopsy apparatus

ABSTRACT

A disposable tissue removal device comprises a “tube within a tube” cutting element mounted to a handpiece. The inner cannula of the cutting element defines an inner lumen and terminates in an inwardly beveled, razor-sharp cutting edge. The inner cannula is driven by both a rotary motor and a reciprocating motor. At the end of its stroke, the inner cannula makes contact with the cutting board to completely sever the tissue. An aspiration vacuum is applied to the inner lumen to aspirate excised tissue through the inner cannula and into a collection trap that is removably mounted to the handpiece. The rotary and reciprocating motors are hydraulically powered through a foot pedal operated hydraulic circuit. The entire biopsy device is configured to be disposable. In one embodiment, the cutting element includes a cannula hub that can be connected to a fluid source, such as a valve-controlled saline bag.

RELATED APPLICATIONS

[0001] The present application is a continuation-in-part of U.S.application Ser. No. 09/707,022 filed on Nov. 6, 2000 in the name ofinventor Michael E. Miller and assigned to the assignee of the presentapplication.

FIELD OF THE INVENTION

[0002] This invention relates to biopsy instruments and methods fortaking a biopsy. More specifically, this invention relates to disposablebiopsy devices for removing several tissue samples using a singleinsertion.

BACKGROUND OF THE INVENTION

[0003] In the diagnosis and treatment of breast cancer, it is oftennecessary to remove multiple tissue samples from a suspicious mass. Thesuspicious mass is typically discovered during a preliminary examinationinvolving visual examination, palpitation, X-ray, MRI, ultrasoundimaging or other detection means. When this preliminary examinationreveals a suspicious mass, the mass must be evaluated by taking a biopsyin order to determine whether the mass is malignant or benign. Earlydiagnosis of breast cancer, as well as other forms of cancer, canprevent the spread of cancerous cells to other parts of the body andultimately prevent fatal results.

[0004] A biopsy can be performed by either an open procedure or apercutaneous method. The open surgical biopsy procedure first requireslocalization of the lesion by insertion of a wire loop, while usingvisualization technique, such as X-ray or ultrasound. Next, the patientis taken to a surgical room where a large incision is made in thebreast, and the tissue surrounding the wire loop is removed. Thisprocedure causes significant trauma to the breast tissue, often leavingdisfiguring results and requiring considerable recovery time for thepatient. This is often a deterrent to patients receiving the medicalcare they require. The open technique, as compared to the percutaneousmethod, presents increased risk of infection and bleeding at the samplesite. Due to these disadvantages, percutaneous methods are oftenpreferred.

[0005] Percutaneous biopsies have been performed using either FineNeedle Aspiration or core biopsy in conjunction with real-timevisualization techniques, such as ultrasound or mammography (X-ray).Fine Needle Aspiration involves the removal of a small number of cellsusing an aspiration needle. A smear of the cells is then analyzed usingcytology techniques. Although Fine Needle Aspiration is less intrusive,only a small amount of cells are available for analysis. In addition,this method does not provide for a pathological assessment of thetissue, which can provide a more complete assessment of the stage of thecancer, if found. In contrast, in core biopsy a larger fragment oftissue can be removed without destroying the structure of the tissue.Consequently, core biopsy samples can be analyzed using a morecomprehensive histology technique, which indicates the stage of thecancer. In the case of small lesions, the entire mass may be removedusing the core biopsy method. For these reasons core biopsy ispreferred, and there has been a trend towards the core biopsy method, sothat a more detailed picture can be constructed by pathology of thedisease's progress and type.

[0006] The first core biopsy devices were of the spring advanced,“Tru-Cut” style consisting of a hollow tube with a sharpened edge thatwas inserted into the breast to obtain a plug of tissue. This devicepresented several disadvantages. First, the device would sometimes failto remove a sample, therefore, requiring additional insertions. This wasgenerally due to tissue failing to prolapse into the sampling notch.Secondly, the device had to be inserted and withdrawn to obtain eachsample, therefore, requiring several insertions in order to acquiresufficient tissue for pathology.

[0007] The biopsy apparatus disclosed in U.S. Pat. No. 5,526,822 toBurbank, et al was designed in an attempt to solve many of thesedisadvantages. The Burbank apparatus is a biopsy device that requiresonly a single insertion into the biopsy site to remove multiple tissuesamples. The device incorporates a tube within a tube design thatincludes an outer piercing needle having a sharpened distal end forpiercing the tissue. The outer needle has a lateral opening forming atissue receiving port. The device has an inner cannula slidinglydisposed within the outer cannula, and which serves to cut tissue thathas prolapsed into the tissue receiving port. Additionally, a vacuum isused to draw the tissue into the tissue receiving port.

[0008] Vacuum assisted core biopsy devices, such as the Burbankapparatus, are available in handheld (for use with ultrasound) andstereotactic (for use with X-ray) versions. Stereotactic devices aremounted to a stereotactic unit that locates the lesion and positions theneedle for insertion. In preparation for a biopsy using a stereotacticdevice, the patient lies face down on a table, and the breast protrudesfrom an opening in the table. The breast is then compressed andimmobilized by two mammography plates. The mammography plates createimages that are communicated in real-time to the stereotactic unit. Thestereotactic unit then signals the biopsy device and positions thedevice for insertion into the lesion by the operator.

[0009] In contrast, when using the handheld model, the breast is notimmobilized. Rather the patient lies on her back and the doctor uses anultrasound device to locate the lesion. The doctor must thensimultaneously operate the handheld biopsy device and the ultrasounddevice.

[0010] Although the Burbank device presents an advancement in the fieldof biopsy devices, several disadvantages remain and further improvementsare needed. For example, the inner cutter must be advanced manually,meaning the surgeon manually moves the cutter back and forth by lateralmovement of a knob mounted on the outside of the instrument or by one ofthe three pedals at the footswitch. Also, the vacuum source that drawsthe tissue into the receiving port is typically supplied via a vacuumchamber attached to the outer cannula. The vacuum chamber defines atleast one, usually multiple, communicating holes between the chamber andthe outer cannula. These small holes often become clogged with blood andbodily fluids. The fluids occlude the holes and prevent the aspirationfrom drawing the tissue into the receiving port. This ultimatelyprevents a core from being obtained, a condition called a “dry tap.”

[0011] In addition, many of the components of the current biopsy devicesare reusable, such as the driver portions, which control the outer andinner needles. This poses several notable disadvantages. First, thereusable portion must be cleaned and/or sterilized. This increases thetime necessary to wrap up the procedure, which ultimately affects thecost of the procedure. In addition, the required clean-up and/orsterilization of reusable parts increases the staffs' potential exposureto body tissues and fluids. Finally, the reusable handle is heavy, largeand cumbersome for handheld use.

[0012] A further disadvantage is that current biopsy devices comprise anopen system where the tissue discharge port is simply an open area ofthe device. A surgical assistant must remove the tissue from the opencompartment using forceps and place the tissue on a sample plate. Thisritual must be followed for every sample and, therefore, multipleoperators are required. In addition, the open system increases theexposure to potentially infectious materials, and requires increasedhandling of the sample. As a practical matter, the open system alsosubstantially increases the clean-up time and exposure, because asignificant amount of blood and bodily fluid leaks from the device ontothe floor and underlying equipment.

[0013] Additionally, when using the current biopsy devices, physicianshave encountered significant difficulties severing the tissue. Forinstance, the inner cutter often fails to completely sever the tissue.When the inner cutting needle is withdrawn, no tissue sample is present(dry tap), and therefore, reinsertion is required. In the case of theBurbank apparatus, the failure to completely sever the tissue after thefirst advancement of the inner cutter results in a necessary secondadvancement of the inner cutter. In this event, the procedure isprolonged, which is significant because the amount of trauma to thetissue and, ultimately, to the patient is greatly affected by the lengthof the procedure. Therefore, it is in the patient's best interest tominimize the length of the procedure by making each and every attempt atcutting the tissue a successful and complete cut.

[0014] Additionally, when using the “tube within a tube” type biopsydevice, the inner cutter can lift up into the tissue receiving openingduring cutting. This lifting causes the inner cutter to catch on theedge of the tissue receiving opening, which ultimately results in anincomplete cut and dulling of the blade, rendering the blade useless.

[0015] Also, prior devices often produce small tissue samples. As theinner cutter advances, the cutting edge not only starts to sever thetissue, it also pushes the tissue in front of the cutter. This resultsin a tissue sample that is smaller than the amount of tissue drawn intothe tissue receiving opening.

[0016] An additional disadvantage of the prior devices is presented bythe complexity of the three-pedal footswitch. Prior devices utilized athree-pedal footswitch; one pedal for advancing the inner cannula,another pedal for retracting the inner cannula, and a third pedal forturning on the aspiration. Operation of the three pedals is difficultand awkward.

[0017] These disadvantages become even more significant when using thehandheld biopsy device. For instance, the physician must operate thebiopsy device and the ultrasound probe simultaneously making itparticularly difficult to manually advance of the inner cutter. Inaddition, when an assistant is required to remove each sample from theopen discharge port, use of the handheld device becomes even moreawkward. Due to these disadvantages, many physicians have declined touse the handheld models.

[0018] This is unfortunate because, some lesions that can signify thepossible presence of cancer cannot be seen using the stereotactic unit.In these cases, the doctor must resort to either the handheld device oropen surgical biopsy. Due to the difficulties associated with thehandheld device, doctors often choose the open surgical biopsy, which isparticularly unfortunate because a majority of the lesions that cannotbe seen using the stereotactic unit turn out to be benign. This meansthat the patient has unnecessarily endured a significant amount of painand discomfort; not to mention extended recovery time and disfiguringresults. In addition, the patient has likely incurred a greaterfinancial expense because the open surgical technique is more difficult,time consuming and costly, especially for those patient without healthinsurance.

[0019] The disadvantages of the open surgical technique coupled with theodds that the lesion is benign present a disincentive for the patient toconsent to the biopsy. The added discomfort alone is enough to causemany patients to take the risk that the lesion is benign. The acceptanceof this risk can prove to be fatal for the minority of cases where thelesion is malignant.

[0020] Finally, current vacuum assisted biopsy devices are not capableof being used in conjunction with MRI. This is due to the fact that manyof the components are made of magnetic components that interfere withthe operation of the MRI. It would be desirable to perform biopsies inconjunction with MRI because it currently is the only non-invasivevisualization modality capable of defining the margins of the tumor.

[0021] In light of the foregoing disadvantages, a need remains for atissue removal device that reliably applies a vacuum without becomingplugged with blood and bodily fluids. A need also remains for a tissueremoval device that is entirely disposable so that both exposure tobio-hazard and clean-up time are significantly minimized, whileconvenience is maximized. A further need remains for a tissue removaldevice that completely severs the maximum amount of tissue withoutrequiring numerous attempts at cutting the tissue. A need also remainsfor a tissue removal device that is MRI compatible. Finally, a needremains for a biopsy tissue removal device that is completely automated,therefore making the handheld biopsy device a more efficient andattractive option.

SUMMARY OF THE INVENTION

[0022] The present invention fulfills the aforementioned needs byproviding a disposable tissue removal device comprising a cuttingelement mounted to a handpiece. The cutting element includes an outercannula defining a tissue-receiving opening and an inner cannulaconcentrically disposed within the outer cannula.

[0023] The outer cannula has a trocar tip at its distal end and acutting board snugly disposed within the outer cannula. The innercannula defines an inner lumen that extends the length of the innercannula, and which provides an avenue for aspiration. The inner cannulaterminates in an inwardly beveled, razor-sharp cutting edge and isdriven by, both a rotary motor, and a reciprocating motor. As the innercannula moves past the tissue-receiving opening, the inwardly bevelededge helps to eliminate the risk of catching the edge on thetissue-receiving opening. At the end of its stroke, the inner cannulamakes contact with the cutting board to completely sever the tissue. Thecutting board is made of a material that is mechanically softer than thecutting edge yet hard enough to withstand the force of the innercannula.

[0024] An aspiration is applied to the inner lumen through an aspirationtube. The aspiration tube communicates with a collection trap that isremovably mounted to the handpiece. The aspiration draws the sample intothe tissue-receiving opening and after the tissue is cut, draws thetissue through the inner cannula to a collection trap.

[0025] In a specific embodiment, both the rotary motor and thereciprocating motors are hydraulic motors. Because hydraulic motors donot require any electrical components, this feature allows all of thecomponents to be fabricated of MRI compatible materials.

[0026] In another embodiment, the tissue-receiving opening is formed byopposite longitudinal edges that form a number of teeth. The teeth faceaway from the cutting board at the distal end of the outer cannula. Theteeth help prevent the forward motion of the tissue in the opening asthe inner cannula moves forward toward the cutting board. This featuremaximizes the length and overall size of the core, ultimately resultingin a more efficient lesion removal.

[0027] In another embodiment, the outer cannula incorporates astiffening element opposite the tissue-receiving opening. Thisstiffening element aids in maintaining the longitudinal integrity of theouter cannula as it is advanced through the tissue.

[0028] In addition to the inwardly beveled edge of the inner cannula,one embodiment incorporates additional features to prevent the innercannula from rising up into the tissue-receiving opening. A bead ofstiffening material may be affixed to the inner wall of the outercannula, or a dimple may be formed in the inner wall of the outercannula. The bead, or dimple urges the inner cannula away from thetissue-receiving opening and prevents the inner cannula from catching onthe opening.

DESCRIPTION OF THE FIGURES

[0029]FIG. 1 is a top perspective view of a tissue biopsy apparatus inaccordance with one embodiment of the present invention.

[0030]FIG. 2 is a top elevational view of the tissue biopsy apparatusshown in FIG. 1.

[0031]FIG. 3A and FIG. 3B are side cross-sectional views of the tissuebiopsy apparatus depicted in FIGS. 1 and 2, with the tissue cuttinginner cannula shown in its retracted and extended positions.

[0032]FIG. 4 is a perspective view of a cover for the tissue biopsyapparatus as shown FIG. 1.

[0033]FIG. 5 is an enlarged side cross-sectional view of the operatingend of the tissue biopsy apparatus depicted in FIGS. 1 and 2.

[0034]FIG. 6 is a side partial cross-sectional view of working end of atissue biopsy apparatus in accordance with an alternative embodiment.

[0035]FIG. 7 is an end cross-sectional view of the apparatus depicted inFIG. 6, taken along line 7-7 as viewed in the direction of the arrows.

[0036]FIG. 8 is an end cross-sectional view similar to FIG. 7 showing amodified configuration for a stiffening member.

[0037]FIG. 8(a) is an end cross-sectional view similar to FIG. 7 showinga modified configuration for another stiffening member.

[0038]FIG. 9 is an enlarged side cross-sectional view of a fluidintroduction port at the hub connecting the outer cannula to thehandpiece for a tissue biopsy apparatus as depicted in FIG. 1.

[0039]FIG. 10 is a schematic drawing of the hydraulic control system forthe operation of the tissue biopsy apparatus shown in FIG. 1.

[0040]FIG. 11 is a schematic drawing of a control system for an electricrotary motor for use with the apparatus of the present invention.

[0041]FIG. 12 is a top elevational view of a tissue biopsy apparatusaccording to a further embodiment of the present invention.

[0042]FIG. 13 is a side cross-sectional view of the biopsy apparatusshown in FIG. 12, taken along line 13-13 as viewed in the direction ofthe arrows.

[0043]FIG. 14 is a side cross-sectional view of a motor assemblyincorporated into the biopsy apparatus shown in FIG. 12.

[0044]FIG. 15 is an end elevational view from the left end of theassembly depicted in FIG. 14.

[0045]FIG. 16 is an end elevational view of the right end of theassembly depicted in FIG. 14.

[0046]FIG. 17 is a top elevational view of a rotary motor assembly inaccordance with one specific embodiment of the invention.

[0047]FIG. 18 is a side elevational view of a cannula hub for engagementwith the assembly depicted in FIG. 14.

[0048]FIG. 19 is a rear elevational view of the cannula hub shown inFIG. 18.

[0049]FIG. 20 is a side cross-sectional view of the cannula hub shown inFIG. 18.

[0050]FIG. 21 is a top perspective view of an upper housing component ofthe biopsy apparatus depicted in FIG. 12.

[0051]FIG. 22 is an end cross-sectional view of the upper housing shownin FIG. 21, taken along line 22-22 as viewed in the direction of thearrows.

[0052]FIG. 23 is a top perspective view of a lower housing for use withthe biopsy apparatus shown in FIG. 12.

[0053]FIG. 24 is a top elevational view of the lower housing shown inFIG. 23.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] For the purposes of promoting an understanding of the principlesof the invention, reference will now be made to the embodimentsillustrated in the drawings and specific language will be used todescribe the same. It will nevertheless be understood that no limitationof the scope of the invention is thereby intended. The inventionincludes any alterations and further modifications in the illustrateddevices and described methods and further applications of the principlesof the invention which would normally occur to one skilled in the art towhich the invention relates.

[0055] A tissue biopsy apparatus 10 in accordance with one embodiment ofthe present invention is shown in FIGS.

[0056] The apparatus 10 includes a cutting element 11 mounted to ahandpiece 12. The cutting element 11 is sized for introduction into ahuman body. Most particularly, the present invention concerns anapparatus for excising breast tissue samples. Thus, the cutting element11 and the overall biopsy apparatus 10 are configured for ease of use inthis surgical environment. In the illustrated embodiment, the biopsyapparatus 10 is configured as a hand-held device. However, the sameinventive principles can be employed in a tissue biopsy apparatus thatis used stereotatically in which the apparatus is mounted on a supportfixture that is used to position the cutting element 11 relative to thetissue to be sampled. Nevertheless, for the purposes of understandingthe present invention, the tissue biopsy apparatus will be described asa hand-held device.

[0057] The cutting element 11 is configured as “tube-within-a-tube”cutting device. More specifically, the cutting element 11 includes anouter cannula 15 terminating in a tip 16. Preferably, the tip is atrocar tip that can be used to penetrate the patient's skin.Alternatively, the tip 16 can simply operate as a closure for the openend of the cannula 15. In this instance, a separate introducer would berequired.

[0058] The cutting element 11 further includes an inner cannula 17 thatfits concentrically within the outer lumen 27 (FIG. 5) of the outercannula 15. In the most preferred embodiment, both a rotary motor 20(FIG. 1) and a reciprocating motor 22 drive the inner cannula 17. Bothmotors are supported within the handpiece 12. Again, in accordance withthe preferred embodiment the rotary motor 20 and reciprocating motor 22are configured for simultaneous operation to translate the inner cannula17 axially within the outer cannula 15, while rotating the inner cannula17 about its longitudinal axis.

[0059] One specific configuration of the working end of the cuttingelement 11 is depicted in FIG. 5. The outer cannula 15 defines atissue-receiving opening 25, which communicates with the outer lumen 27.A pair of opposite longitudinal edges 26 (FIGS. 1 and 2) define thetissue-receiving opening 25. The outer cannula 15 is open at its distalend 28 with the trocar tip 16 engaged therein. Preferably, the trocartip 16 forms an engagement hub 30 that fits tightly within the distalend 28 of the outer cannula 15. The hub 30 can be secured by welding,press-fit, adhesive or other means suitable for a surgical biopsyinstrument.

[0060] The working end of the cutting element 11 further includes acutting board 31 that is at least snugly disposed within the outer lumen27 at the distal end 28 of the outer cannula 15. Most preferably, thecutting board 31 is in direct contact with the engagement hub 30 of thetrocar tip 16. The cutting board 31 can be permanently affixed withinthe outer cannula 15 and/or against the engagement hub 30 of the trocartip.

[0061] The inner cannula 17 defines an inner lumen 34 that is hollowalong the entire length of the cannula to provide for aspiration of thebiopsy sample. The inner cannula 17 terminates in a cutting edge 35.Preferably the cutting edge 35 is formed by an inwardly beveled surface36 to provide a razor-sharp edge. The inwardly beveled surface helpseliminate the risk of catching the edge 35 on the tissue-receivingopening 25 of the outer cannula. In addition, the beveled surface 36helps avoid pinching the biopsy material between the inner and outercannulas during a cutting stroke.

[0062] In a specific embodiment, both the outer cannula 15 and the innercannula 17 are formed of a surgical grade metal. Most preferably, thetwo cannulae are formed of stainless steel. In the case of an MRIcompatible device, the cannulae can be formed of Inconel, Titanium orother materials with similar magnetic characteristics. Likewise, thetrocar tip 16 is most preferably formed of stainless steel honed to asharp tip. The trocar tip 16 can be suitably bonded to the outer cannula15, such as by welding or the use of an appropriate adhesive. In someembodiments, the inner and outer cannulae can be formed of anon-metallic material of appropriate strength and stiffness.

[0063] The cutting board 31 is formed of a material that is configuredto reduce the friction between the cutting edge 35 of the inner cannula17 and the cutting board 31. The cutting edge 35 necessarily bearsagainst the cutting board 31 when the inner cannula 17 is at the end ofits stroke while severing a tissue sample. Since the inner cannula isalso rotating, the cuffing edge necessarily bears directly against thecutting board 31, particularly after the tissue sample has been cleanlysevered. In prior devices, the impact-cutting surface has been formed ofthe same material as the cutting element. This leads to significant wearor erosion of the cutting edge. When numerous cuffing cycles are to beperformed, the constant wear on the cutting edge eventually renders itincapable of cleanly severing a tissue sample.

[0064] Thus, the present invention contemplates forming the cuttingboard 31 of a material that reduces this frictional wear. In oneembodiment, the cutting board 31 is formed of a material that ismechanically softer than the material of the cutting edge 35. However,the cutting board 31 cannot be so soft that the cutting edge 35 forms apronounced circular groove in the cutting board, which significantlyreduces the cutting efficiency of the inner cannula. In a most preferredembodiment of the invention, the cutting board 31 is formed of a plasticmaterial, such as polycarbonate, ABS or DELRIN®.

[0065] Returning again to FIGS. 1, 2 and 3A-3B, the rotary motor 20includes a motor housing 39 that is sized to reciprocate within thehandpiece 12. The housing 39 defines a pilot port 40 that is connectedto the hydraulic control system 150 (see FIG. 10) by appropriate tubing.The present invention contemplates that the motor 20 can be a number ofhydraulically powered rotating components. Most preferably, the motor 20is an air motor driven by pressured air. Thus, the motor 20 includes avaned rotor 42 that is mounted on a hollow tubular axle 43 extendingthrough the motor housing 39. The axle 43 is supported on bearings 44 atopposite ends of the housing so that the rotor 42 freely rotates withinthe motor housing 39 under pneumatic pressure.

[0066] In the illustrated embodiment, tubular axle 43 is connected tothe proximal end 37 of the inner cannula 17 by way of a coupler 46. Theends of the two tubes are mounted within the coupler 46 and held inplace by corresponding set screws 47. Preferably the coupler 46 isformed of a plastic material that provides a generally airtight sealaround the joint between the inner cannula 17 and the tubular axle 43.It is important that the coupler 46 provide a solid connection of theinner cannula 17 to the rotating components of the motor 20 so that theinner cannula 17 does not experience any torrential slip during thecutting operation.

[0067] Since the inner cannula 17 provides an avenue for aspiration ofthe biopsy sample, the invention further contemplates an aspiration tube50 that mates with the tubular axle 43. Thus, the tissue aspiration pathfrom the working end of the cutting element 11 is along the inner lumen34 of the inner cannula 17, through the tubular axle 43 of the rotarymotor 20, and through the aspiration tube 50 to a tissue collectionlocation in the form of a collection trap 55. In order to maintain thevacuum or aspiration pressure within this aspiration path, theaspiration tube 50 must be fluidly sealed against the tubular axle 43.Thus, the motor housing 39 defines a mounting hub 51 into which theaspiration tube 50 is engaged. The position of the aspiration tube 50 isfixed by way of a set screw 52 passing through the mounting hub 51. Incontrast to the joint between the inner cannula 17 and the tubular axle43, the joint between the aspiration tube 50 and the tubular axle 43allows relative rotational between the two components. The tubular axle43, of course, rotates with the rotor 42. However, the aspiration tube50 need not rotate for use with the biopsy apparatus of the presentinvention. The mounting hub 51 can include an arrangement of seal rings(not shown) at the joint between the aspiration tube 50 and the tubularaxle 43 to further seal the aspiration system.

[0068] The aspiration tube 50 communicates with a collection trap 55that is removably mounted to the handpiece 12. The collection trap 55includes a pilot port 107 that is connected by appropriate tubing to thehydraulic control system 150, as described in more detail herein. Forthe present purposes, it is understood that a vacuum or aspirationpressure is drawn through the pilot port 107 and the collection trap 55.This vacuum then draws a tissue sample excised at the working end of thecutting element 11, all the way through the inner cannula 17, tubularaxle 43 and aspiration tube 50 until it is deposited within the trap.Details of the collection trap 55 will be discussed herein.

[0069] As explained above, the present invention contemplates an innercannula 17 that performs its cutting operation by both rotary andreciprocating motion. Thus, the handpiece 12 supports a reciprocatingmotor 22. In one aspect of the invention, both motors 20 and 22 arehydraulically powered, most preferably pneumatically. This featureallows the motors to be formed of plastic, since no electricalcomponents are required. In fact, with the exception of the outercannula 15, trocar tip 16 and inner cannula 17, every component of thebiopsy apparatus 10 in accordance with the present invention can beformed of a non-metallic material, most preferably a medical gradeplastic. Thus, the biopsy apparatus 10 is eminently compatible withsurgical imaging systems that may be used during the biopsy procedure.The compatibility of the apparatus 10 with Magnetic Resonance Imaging(MRI) is important because MRI is currently the only non-invasivevisualization modality capable of defining the margins of the tumor. Inaddition, since the biopsy apparatus is formed of a relativelyinexpensive plastic (as opposed to a more expensive metal), the entireapparatus can be disposable. Moreover, the elimination of substantiallyall metal components reduces the overall weight of the handpiece 12,making it very easily manipulated by the surgeon.

[0070] Referring most specifically to FIGS. 3A and 3B, the reciprocatingmotor 22 includes a pneumatic cylinder 60. The cylinder 60 includes apilot port 61 that connects the cylinder to the hydraulic control system150 through appropriate tubing. The motor 22 includes a piston 63 thatreciprocates within the cylinder 60 in response to hydraulic fluidpressure provided at the pilot port 61. The piston 63 includes a centralbore 64 for mounting the piston 63 to the aspiration tube 50. In oneembodiment, the aspiration tube 50 is press-fit within the bore 64. Theengagement between the aspiration tube 50 and the piston 63 can beenhanced by use of a set screw (not shown) or an adhesive or epoxy. Atany rate, it is essential that the aspiration tube 50 and piston 63 movetogether, since the motor 22 must eventually drive the inner cannula 17axially within the outer cannula.

[0071] It should be understood that in addition to powering the innercannula, the piston 63 also reciprocates the rotary motor 20, which isessentially mounted to the reciprocating aspiration conduit. Thismovement is depicted by comparing the position of the rotary motor 20between FIG. 3A and FIG. 3B. More specifically, the motor 20 as well asthe aspiration conduit, including the inner cannula 17, moves within thehandpiece 12. Preferably, the handpiece housing 70 is provided withopenings 73 (FIG. 3B) at its opposite ends for slidably supporting theaspiration tube 50 and inner cannula 17. Since the distal housing 70 ispreferably formed of a plastic material, no thrust bearings or rotarybearings are necessary to accommodate low friction axial movement of thecannula through the housing openings 73.

[0072] The biopsy apparatus 10 includes a handpiece 12 that carries allof the operating components and supports the outer and inner cannulas.The handpiece 12 includes a distal housing 70 within which is disposedthe rotary motor 20. The distal end 71 of the housing 70 is configuredinto a fitting 72. This fitting 72 engages a mating flange 77 on anouter cannula hub 75. The hub 75 supports the outer cannula 15 within anengagement bore 76 (see FIG. 3B).

[0073] In accordance with one aspect of the present invention, theengagement between the outer cannula hub 75 and the distal end 71 of thehousing 70 need not be airtight. In other words, the mating componentsof the fitting between the two parts need not be capable of generating afluid-tight seal. In accordance with one embodiment of the invention,the engagement between the hub 75 and the housing 70 for supporting theouter cannula 15 provides a leak path through the outer lumen 27 to theatmosphere. In the use of the tissue biopsy apparatus 10, providingaspiration through the inner lumen 34 of the inner cutting cannula 17will draw tissue through the inner lumen. As the tissue advances fartheralong the lumen, in some instances a vacuum can be created behind theadvancing tissue. At some point in these instances, the tissue will stopadvancing along the length of the inner lumen because the vacuum behindthe tissue sample equals the vacuum in front of the tissue sample thatis attempting to draw the sample to the collection trap 55. Thus, theleak path through the outer lumen 27 allows atmospheric air to fall inbehind the tissue sample when the inner cutter is retracted from thecutting board. The atmospheric air helps to relieve the vacuum behindthe advancing tissue and aids in drawing the tissue down the length ofthe aspiration channel to the collection trap 55. However, in someapplications, particularly where smaller “bites” of the target tissueare taken, the atmospheric air leak path is not essential.

[0074] Preferably the fitting 72 and the mating flange 77 can be engagedby simple twisting motion, most preferably via Luer-type fittings. Inuse, the cannula hub 75 is mounted on the handpiece 12, therebysupporting the outer cannula 15. The handpiece can then be used toproject the outer cannula into the body adjacent the sample site. Incertain uses of the biopsy apparatus 10, it is desirable to remove thehandpiece 12 from the cannula hub 75 leaving the outer cannula 15 withinthe patient. For example, the outer cannula 15 can be used to introducean anesthetic. In other applications, once the target tissue has beencompletely excised, the outer cannula can be used to guide aradio-opaque marker to mark the location the removed material.

[0075] Returning again to the description of the housing 70, the housingdefines an inner cavity 79 that is open through an access opening 81.The access opening 81 is preferably provided to facilitate assembly ofthe tissue biopsy apparatus 10. The distal end 71 of the housing 70 canbe provided with a pair of distal braces 80 that add stiffness to thedistal end 71 while the apparatus is in use. The braces 80 allow thedistal housing 70 to be formed as a thin-walled plastic housing. Similarbraces can be provided at the opposite end of the distal housing asnecessary to add stiffness to the housing.

[0076] The distal housing is configured to support the reciprocatingmotor 22 and in particular the cylinder 60. Thus, in one embodiment ofthe invention, the proximal end 83 of the distal housing 70 defines apressure fitting 84. It is understood that this pressure fitting 84provides a tight leak-proof engagement between the distal end 88 of thecylinder 60 and the proximal end 83 of the housing. In one specificembodiment, the pressure fitting 84 forms a spring cavity 85 withinwhich a portion of the return spring 66 rests. In addition, in aspecific embodiment, the pressure fitting 84 defines distal piston stop86. The piston 63 contacts these stops at the end of its stroke. Thelocation of the piston stop 86 is calibrated to allow the cutting edge35 to contact the cutting board 31 at the working end of the cuttingelement 11 to allow the cutting edge to cleanly sever the biopsy tissue.

[0077] In the illustrated embodiment, the cylinder 60 is initiallyprovided in the form of an open-ended cup. The open end, correspondingto distal end 88, fastens to the pressure fitting 84. In specificembodiments, the pressure fitting can include a threaded engagement, apress-fit or an adhesive arrangement.

[0078] The cylinder cup thus includes a closed proximal end 89. Thisproximal end defines the pilot port 61, as well as a central opening 62(FIG. 3B) through which the aspiration tube 50 extends. Preferably, theproximal end 89 of the cylinder 60 is configured to provide asubstantially airtight seal against the aspiration tube 50 even as itreciprocates within the cylinder due to movement of the piston 63. Theproximal end 89 of the cylinder 60 defines a proximal piston stop 90,which can either be adjacent the outer cylinder walls or at the centerportion of the proximal end. This proximal piston stop 90 limits thereverse travel of the piston 63 under action of the return spring 66when pressure within the cylinder has been reduced.

[0079] In a further aspect of the invention, the collection trap 55 ismounted to the handpiece 12 by way of a support housing 93. It should beunderstood that in certain embodiments, the handpiece 12 can be limitedto the previously described components. In this instance, the collectiontrap 55 can be situated separate and apart from the handpiece,preferably close to the source of vacuum or aspiration pressure. In thiscase, the proximal end of the aspiration tube 50 would be connected tothe collection trap by a length of tubing. In the absence of thecollection trap 55, the aspiration tube 50 would reciprocate away fromand toward the proximal end of the cylinder 60, so that it is preferablethat the handpiece includes a cover configured to conceal thereciprocating end of the aspiration tube.

[0080] However, in accordance with the most preferred embodiment, thecollection trap 55 is removably mounted to the handpiece 12. A pair oflongitudinally extending arms 94, that define an access opening 95therebetween, forms the support housing 93. The support housing 93includes a distal end fitting 96 that engages the proximal end 89 ofcylinder 60. A variety of engagements are contemplated, preferably inwhich the connection between the two components is generally airtight.The proximal end 97 of the support housing 93 forms a cylindricalmounting hub 98. As best shown in FIG. 1, the mounting hub 98 surroundsa proximal end of the collection trap 55. The hub forms a bayonet-typemounting groove 99 that receives pins 103 attached to the housing 102 ofthe trap 55. A pair of diametrically opposite wings 104 can be providedon the housing 102 to facilitate the twisting motion needed to engagethe bayonet mount between the collection trap 55 and the support housing93. While the preferred embodiment contemplates a bayonet mount, otherarrangements for removably connecting the collection trap 55 to thesupport housing 93 are contemplated. To be consistent with one of thefeatures of the invention, it is preferable that this engagementmechanism be capable of being formed in plastic.

[0081] In order to accommodate the reciprocating aspiration tube, thesupport housing 93 is provided with an aspiration passageway 100 thatspans between the proximal and distal ends of the housing. Since theaspiration tube 50 reciprocates, it preferably does not extend into thecollection trap 55. As excised tissue is drawn into the trap 55, areciprocating aspiration tube 50 can contact the biopsy materialretained within the trap. This movement of the tube can force tissueinto the end of the tube, clogging the tube. Moreover, the reciprocationof the aspiration tube can compress tissue into the end of the trap,thereby halting the aspiration function.

[0082] The collection trap 55 includes a housing 102, as previouslyexplained. The housing forms a pilot port 107, which is connectable to avacuum generator. Preferably in accordance with the present invention,appropriate tubing to the hydraulic control system 150 connects thepilot port 107. The trap 55 includes a filter element 110 mounted withinthe trap. In the preferred embodiment, the filter element is a meshfilter than allows ready passage of air, blood and other fluids, whileretaining excised biopsy tissue samples, and even morcellized tissue. Inaddition, the filter element 110 is preferably constructed so thatvacuum or aspiration pressure can be drawn not only at the bottom end ofthe filter element, but also circumferentially around at least aproximal portion of the element 110. In this way, even as material isdrawn toward the proximal end of the filter, a vacuum can still be drawnthrough other portions of the filter, thereby maintaining the aspirationcircuit.

[0083] The handpiece 12 can include individual covers for closing theaccess opening 81 in the distal housing 70 and the access openings 95 inthe support housing 93. Those covers can support tubing for engagementwith the pilot ports 40 and 61. Alternatively and most preferably, asingle cover 13 as depicted in FIG. 4, is provided for completelyenclosing the entire handpiece. The distal end 71 of the housing 70 candefine a number of engagement notches 115 equally spaced around theperimeter of the distal end. The handpiece cover 13 can then include alike number of equally distributed tangs 117 projecting inwardly fromthe inner surface from the 118. These tangs are adapted to snap into theengagement notches 115 to hold the cover 113 in position over thehandpiece 12. The cover can be attached by sliding axially over thehandpiece 12. The cover 13 can include fittings for fluid engagementwith the two pilot ports 40 and 61. Alternatively, the cover can beformed with openings for insertion of engagement tubing to mate with therespective pilot ports to provide hydraulic fluid to the rotary motor 20and the reciprocating motor 22. In a specific embodiment, the cover 13extends from the distal end 71 of the distal housing 70 to the proximalend 97 of the support housing 93. The cover can thus terminate short ofthe bayonet mounting feature between the support housing and thecollection trap 55. Although not shown in the figures, the proximal end97 of the support housing 93 can be configured to include a similararray of engagement notches with a corresponding array of mating tangsformed at the proximal end of the cover 13.

[0084] It can be appreciated from the foregoing discussion that thebiopsy apparatus 10 of the present invention provides a complete“closed” tissue excision and recovery system. In other words, unlikeprior biopsy devices, the apparatus 10 is fluid tight so that no bodilyfluids can escape. Biopsy procedures with many prior devices involvessignificant blood splatter due to the nature in which the tissue samplesare extracted and recovered. With the present invention, the biopsyapparatus 10 provides a closed path from the tissue receiving opening 25to the collection trap 55, while still maintaining the highly efficientreciprocating and rotating cutting operation.

[0085] Referring now to FIGS. 6-8, alternative embodiments of the outercannula are depicted. As shown in FIG. 6 an outer cannula 125 includes atissue-receiving opening 126. The opening is formed by oppositelongitudinal edges 127. In one specific embodiment, a number of teeth129 are formed at each longitudinal edge 127. As depicted in the figure,the teeth are proximally facing—i.e., away from the cutting board 31(not shown) at the distal end of the outer cannula. With thisorientation, the teeth 129 help prevent forward motion of tissue drawninto the opening 126 as the inner cannula 17 moves forward toward thecutting board. In prior devices, as the reciprocating cutting elementadvances through the outer cannula, the cutting edge not only starts tosever the tissue, it also pushes tissue in front of the inner cannula.Thus, with these prior devices, the ultimate length of the biopsy sampleretrieved with the cut is smaller than the amount of tissue drawn intothe tissue-receiving opening of the outer cannula. With the teeth 129 ofthe outer cannula 125 of this embodiment of the invention, the tissuesample removed through the inner cannula 17 is substantially the samelength as the tissue-receiving opening 126. As the inner cannula 17advances into the tissue, each of the teeth 129 tends to hold the tissuein place as the cutting edge 35 severs the tissue adjacent the outercannula wall. With this feature, each “bite” is substantially as largeas possible so that a large tissue mass can be removed with much fewer“bites” and in a shorter period of time. In addition to supporting thesubject tissue as the inner cannula advances, the teeth can also cutinto the tissue to prevent it from retracting out of the opening as theinner cuffing cannula 17 advances.

[0086] The outer cannula 125 depicted in FIG. 6 can also incorporate astiffening element 131 opposite the tissue-receiving opening 126. Thestiffening element 131 adds bending stiffness to the outer cannula 125at the distal end in order to maintain the longitudinal integrity of theouter cannula 125 as it is advanced into a tissue mass. In some priordevices that lack such a stiffening element, the working end of thecutting device is compromised as it bends slightly upward or downward asthe outer cannula passes into the body. This bending can either close orexpand the tissue-receiving opening, which leads to difficulties inexcising and retrieving a tissue sample. The cutting mechanism of thepresent invention relies upon full, flush contact between the cuttingedge of the inner cannula 17 and the cutting board 31. If the end of theouter cannula 125 is slightly askew, this contact cannot be maintained,resulting in an incomplete slice of the tissue sample.

[0087] As depicted in the cross-sectional view of the FIG. 7, thestiffening element 131 in one embodiment is a crimp extendinglongitudinally in the outer wall of the cannula substantially coincidentwith the tissue-receiving opening 126. The outer cannula 125′ depictedin FIG. 8 shows two additional versions of a stiffening element. In bothcases, a bead of stiffening material is affixed to the outer cannula.Thus in one specific embodiment, a bead 131′ is adhered to the innerwall of the outer cannula. In a second specific embodiment, a bead 131″is affixed to the outside of the outer cannula. In either case, thebeads can be formed of a like material with the outer cannula, and inboth cases, the beads provide the requisite additional bendingstiffness. Another version of a stiffening element is shown if FIG.8(a). In this case, a layer 131′″ of additional stainless steel isbonded to the outer wall of the outer cannula 125″.

[0088] Returning to FIG. 6, a further feature that can be integratedinto the outer cannula 125 is the dimple 135. One problem frequentlyexperienced by tube-within-a-tube cutters is that the innerreciprocating cutter blade contacts or catches on the outer cannula atthe distal edge of the tissue-receiving opening. With the presentinvention, the dimple 135 urges the inner cannula 17 away from thetissue-receiving opening 126. In this way, the dimple prevents thecutting edge of the inner cannula 17 from catching on the outer cannulaas it traverses the tissue-receiving opening. In the illustratedembodiment of FIG. 6, the dimple 135 is in the form of a slight crimp inthe outer cannula 125. Alternatively, as with the different embodimentsof the stiffening element, the dimple 135 can be formed by a protrusionaffixed or adhered to the inner surface of the outer cannula.Preferably, the dimple 135 is situated immediately proximal to thetissue-receiving opening to help maintain the distance between thecutting edge and the tissue-receiving opening.

[0089] As previously described, the outer cannula 15 is supported by ahub 75 mounted to the distal end of the handpiece. In an alternativeembodiment depicted in FIG. 9, the outer cannula hub 140 provides a meanfor introducing fluids into the outer lumen 27 of the outer cannula.Thus, the hub 140 includes an engagement bore 141 within which the outercannula 15 is engaged. The hub also defines a flange 142 configured formating with the fitting 72 at the distal end 71 of the housing 70. Thus,the outer cannula hub 140 is similar to the hub 75 described above. Withthis embodiment, however, an irrigation fitting 145 is provided. Thefitting defines an irrigation lumen 146 that communicates with theengagement bore 141.

[0090] Ultimately, this irrigation lumen is in fluid communication withthe outer lumen 27 of the outer cannula 15. The irrigation fitting 145can be configured for engagement with a fluid-providing device, such asa syringe. The hub 140 thus provides a mechanism for introducingspecific fluids to the biopsy site. In certain procedures, it may benecessary to introduce additional anesthetic to the sampling site, whichcan be readily accommodated by the irrigation fitting 145.

[0091] As discussed above, the preferred embodiment of the tissue biopsyapparatus 10 according to the present invention relies upon hydraulicsor pneumatics for the cutting action. Specifically, the apparatusincludes a hydraulic rotary motor 20 and a hydraulic reciprocating motor22. While the apparatus 10 can be adapted for taking a single biopsyslice, the preferred use is to completely remove a tissue mass throughsuccessive cutting slices. In one typical procedure, the cutting element11 is positioned directly beneath a tissue mass, while an imaging deviceis disposed above the mass. The imaging device, such as an ultra-soundimager, provides a real-time view of the tissue mass as the tissuebiopsy apparatus 10 operates to successively remove slices of the mass.Tissue is continuously being drawn into the cutting element 11 by theaspiration pressure or vacuum drawn through the inner cannula 17.Successive reciprocation of the inner cannula 17 removes large slices ofthe mass until it is completely eliminated.

[0092] In order to achieve this continuous cutting feature, the presentinvention contemplates a hydraulic control system 150, as illustrated inthe diagram of FIG. 10. Preferably the bulk of the control system ishoused within a central console. The console is connected to apressurized fluid source 152. Preferably the fluid source provides aregulated supply of filtered air to the control system 150.

[0093] As depicted in this diagram of FIG. 10, pressurized fluid fromthe source as provided at the several locations 152 throughout thecontrol system. More specifically, pressurized fluid is provided to fivevalves that form the basis of the control system.

[0094] At the left center of the diagram of FIG. 10, pressurized fluid152 passes through a pressure regulator 154 and gauge 155. The gauge 155is preferably mounted on the console for viewing by the surgeon ormedical technician. The pressure regulator 154 is manually adjustable tocontrol the pressurized fluid provided from the source 152 to thetwo-position hydraulic valve 158. The valve 158 can be shifted between aflow path 158 a and a flow path 158 b. A return spring 159 biases thehydraulic valve to its normal position 158 a.

[0095] In the normally biased position of flow path 158 a, the valve 158connects cylinder pressure line 161 to the fluid source 152. Thispressure line 161 passes through an adjustable flow control valve 162that can be used to adjust the fluid flow rate through the pressure line161. Like the pressure gauge 155 and pressure regulator 154, theadjustable flow control valve 162 can be mounted on a console formanipulation during the surgical procedure.

[0096] The pressure line 161 is connected to the pilot port 61 of thereciprocating motor 22. Thus, in the normal or initial position of thehydraulic control system 150, fluid pressure is provided to the cylinder60 to drive the piston 63 against the biasing force of the return spring66. More specifically with reference to FIG. 3B, the initial position ofthe hydraulic valve 158 is such that the reciprocating motor and innercannula are driven toward the distal end of the cutting element. In thisconfiguration, the inner cannula 17 covers the tissue-receiving opening25 of the outer cannula 15. With the inner cannula so positioned, theouter cannula can be introduced into the patient without risk of tissuefilling the tissue-receiving opening 25 prematurely.

[0097] Pressurized fluid along cylinder pressure 161 is also fed to apressure switch 165. The pressure switch has two positions providingflow paths 165 a and 165 b. In addition, an adjustable return spring 166biases this switch to its normal position at which fluid from thepressure source 152 terminates within the valve. However, whenpressurized fluid is provided through cylinder pressure line 161, thepressure switch 165 moves to its flow path 165 b in which the fluidsource 152 is hydraulically connected to the pressure input line 168.This pressure input line 168 feeds an oscillating hydraulic valve 170.It is this valve that principally operates to oscillate thereciprocating motor 22 by alternately pressurizing and releasing thetwo-position hydraulic valve 158. The pressure switch 165 is calibratedto sense an increase in pressure within the cylinder pressure line 161or in the reciprocating motor cylinder 60 that occurs when the piston 66has reached the end of its stroke. More specifically, the piston reachesthe end of its stroke when the inner cannula 17 contacts the cuttingboard 31. At this point, the hydraulic pressure behind the pistonincreases, which increase is sensed by the pressure valve 165 to strokethe valve to the flow path 165 b.

[0098] The oscillating hydraulic valve 170 has two positions providingflow paths 170 a and 170 b. In position 170 a, input line 179 is fed tooscillating pressure output line 172. With flow path 170 b, the inputline 179 is fed to a blocked line 171. Thus, with fluid pressureprovided from pressure switch 165 (through flow path 165 b), theoscillating valve 170 opens flow path 170 a which completes a fluidcircuit along output line 172 to the input of the hydraulic valve 158.

[0099] Fluid pressure to output line 172 occurs only when there is fluidpressure within input line 179. This input line is fed by valve 176,which is operated by foot pedal 175. The valve 176 is biased by a returnspring 177 to the initial position of flow path 176 a. However, when thefoot pedal 175 is depressed, the valve 176 is moved against the force ofthe spring to flow path 176 b. In this position, pressurized fluid fromthe source 152 is connected to the foot pedal input line 179. When theoscillating hydraulic valve 170 is in its initial position flow path 170a, pressurized fluid then flows through input line 179 to output line172 and ultimately to the hydraulic valve 158.

[0100] The fluid pressure in the output line 172 shifts the valve 158 tothe flow path 158 b. In this position, the fluid pressure behind thepiston 63 is relieved so that the return spring 66 forces the pistontoward the proximal end. More specifically, the return spring retractsthe inner cannula 17 from the tissue cutting opening 25. The relief ofthe fluid pressure in line 161 also causes the pressure switch 165 toreturn to its initial neutral position of flow path 165 a, due to theaction of the return spring 166. In turn, with the flow path 165 a, thepressure input line 168 is no longer connected to the fluid source 152,so no pressurized fluid is provided to the oscillating hydraulic valve170. Since this valve is not spring biased to any particular state, itsposition does not necessarily change, except under conditions describedherein.

[0101] Returning to the foot pedal 175 and valve 176, once the footpedal is released, the biasing spring 177 forces the valve 176 from itsflow path 176 b to its normal initial flow path 176 a. In this positionthe foot pedal input line 179 is no longer connected to the fluid source152. When the oscillating valve 170 is at flow path 170 a, the fluidpressure through output line 172 is eliminated. In response to thisreduction in fluid pressure, hydraulic valve 158 is shifted to itsoriginal flow path 158 a by operation of the return spring 159. In thisposition, the cylinder pressure line 161 is again connected to the fluidsource 152, which causes the reciprocating motor 22 to extend the innercannula 17 to its position blocking the tissue-receiving opening 25.Thus, in accordance with the present invention, the hydraulic controlsystem 150 starts and finishes the tissue biopsy apparatus 10 with thetissue-receiving opening closed. It is important to have the openingclosed once the procedure is complete so that no additional tissue maybe trapped or pinched within the cutting element 11 as the apparatus isremoved from the patient.

[0102] Thus far the portion of the hydraulic control system 150 thatcontrols the operation of the reciprocating motor 22 has been described.The system 150 also controls the operation of the rotary motor 20.Again, in the most preferred embodiment, the motor 20 is an air motor.This air motor is controlled by another hydraulic valve 182. As shown inFIG. 10, the initial position of the valve provides a flow path 182 a inwhich the fluid source 152 is connected to blocked line 183. However,when the hydraulic valve 182 is pressurized, it moves to flow path 182 bin which the fluid source 152 is connected to the pilot port 140 of theair motor. In this position, pressurized fluid continuously drives theair motor 20, thereby rotating the inner cannula 17. It can be notedparenthetically that a muffler M can be provided on the air motor toreduce noise.

[0103] The rotary motor hydraulic valve 182 is controlled by fluidpressure on pressure activation line 180. This activation line 180branches from the foot pedal input line 179 and is connected to the footpedal switch 176. When the foot pedal 175 is depressed, the switch movesto its flow path 176 b. In this position the pressure activation line180 is connected to the fluid source 152 so fluid pressure is provideddirectly to the rotary motor hydraulic valve 182. As with the otherhydraulic valves, the valve 182 includes a biasing spring 184 that mustbe overcome by the fluid pressure at the input to the valve.

[0104] It should be understood that since the fluid control for therotary motor 20 is not fed through the oscillating hydraulic valve 170,the motor operates continuously as long as the foot pedal 175 isdepressed. In addition, it should also be apparent that the speed of therotary motor 20 is not adjustable in the illustrated embodiment. Sincethe motor 20 is connected directly to the fluid source 152, which ispreferably regulated at a fixed pressure, the air motor actuallyoperates at one speed. On the other hand, as discussed above, thereciprocating motor 22 is supplied through a pressure regulator 154 anda flow control valve 162. Thus, the speed of reciprocation of thecutting blade 35 is subject to control by the surgeon or medicaltechnician. The reciprocation of the cutting element 11 can be afunction of the tissue being sampled, the size of the tissue biopsysample to be taken, and other factors specific to the particularpatient. These same factors generally do not affect the slicingcharacteristic of the cutting edge 35 achieved by rotating the innercannula.

[0105] The hydraulic control system 150 also regulates the aspirationpressure or vacuum applied through the aspiration conduit, whichincludes the inner cannula 17. In the illustrated embodiment, thepressure activation line 180 branches to feed an aspiration valve 185.The valve is movable from its initial flow path 185 a to a second flowpath 185 b. In the initial flow path, the fluid source 152 is connectedto a blocked line 186. However, when fluid pressure is applied on line180, the valve 185 shifts against the biasing spring 187 to the flowpath 185 b. In this path, the venturi element 190 is connected to thefluid source. This venturi element thus generates a vacuum in a vacuumcontrol line 193 and in aspiration line 191. Again, as with the airmotor, the venturi element 190 can include a muffler M to reduce noisewithin the handpiece.

[0106] As long as the foot pedal 175 is depressed and the valve 176 isin its flow path 176 b, fluid pressure is continuously applied to theaspiration hydraulic valve 195 and the venturi element 190 generates acontinuous vacuum or negative aspiration pressure. As with the operationof the rotary motor, this vacuum is not regulated in the most preferredembodiment. However, the vacuum pressure can be calibrated by aselection of an appropriate venturi component 190.

[0107] When the venturi component 190 is operating, the vacuum drawn oncontrol line 193 operates on vacuum switch 194. A variable biasingspring 195 initially maintains the vacuum switch 194 at its flow path194 a. In this flow path, the vacuum input line 196 is not connected toany other line. However, at a predetermined vacuum in control line 193,the valve moves to flow path 194 b. In this position, the vacuum inputline 196 is connected to pressure line 192. In the preferred embodiment,the vacuum switch 194 operates in the form of a “go-nogo” switch—inother words, when the aspiration vacuum reaches a predeterminedoperating threshold, the vacuum switch is activated. When the vacuumswitch 184 is initially activated, it remains activated as long as thefoot pedal is depressed. Thus vacuum input line 196 is continuouslyconnected to pressure line 192 as long as the foot pedal 175 isdepressed.

[0108] Looking back to the hydraulic valve 158, the fluid pressure inline 192, and ultimately in vacuum input line 196, is determined by thestate of valve 158. When the valve 158 is in its flow path 158 a inwhich regulated fluid pressure is provided to the reciprocating motor22, the pressure line 192 is dead. However, when the valve 158 moves toflow path 158 b, pressure line 192 is connected to the regulated fluidsource. Pressurized fluid then flows from pressure line 192, throughvacuum switch flow path 194 b, through vacuum input line 196 to the leftside of oscillating valve 170, causing the valve to stroke to flow path170 b. When the oscillating valve 170 is in this flow path, output line172 is dead, which allows valve 158 to move to its flow path 158 a underthe effect of the return spring 159. In this state, valve 158 allowspressurized fluid to again flow to the reciprocating motor 22 causing itto move through the next cutting stroke.

[0109] Thus, when both the valve 158 and the vacuum switch 194 are movedto their alternate states, pressurized fluid passes from line 192,through vacuum input line 196, and through an adjustable flow controlvalve 197 to a second input for the oscillating hydraulic valve 170.Pressure on the vacuum input line 196 shifts the oscillating valve 170to its second position for flow path 170 b. In this position,pressurized fluid passing through the foot pedal valve 176 terminateswithin valve 170. As a consequence, the pressure in output line 172drops which allows the hydraulic valve 158 shift back to its originalposition 158 a under operation of the return spring 159. In thisposition, fluid pressure is again supplied to the reciprocating motor 22to cause the piston 66 to move through its cutting stroke.

[0110] It should be appreciated that the oscillating valve 170 isinfluenced by fluid pressure on lines 168 and 196, and that these lineswill not be fully pressurized at the same time. When the system isinitially energized, pressure from source 152 is automatically suppliedto reciprocating motor 22 and pressure valve 165, causing the valve tomove to flow path 165 b. In this state, line 168 is pressurized whichshifts oscillating valve 170 to the left to state 170 a. The oscillatingvalve will remain in that state until line 196 is pressurized,regardless of the position of pressure switch 165. It can also beappreciated that in the preferred embodiment, the fluid pressure on line196 does not increase to operating levels until the foot pedal 175 hasbeen depressed and the aspiration circuit has reached its operatingvacuum.

[0111] In an alternative embodiment, the vacuum switch 194 can becalibrated to sense fine changes in vacuum. In this alternativeembodiment, the completion of this return stroke can be determined bythe state of the vacuum switch 194. The vacuum switch 194 can operate asan indicator that a tissue sample has been drawn completely through theaspiration conduit into the collection trap 55. More specifically, whenthe vacuum sensed by vacuum switch 194 has one value when the innercannula is open to atmospheric pressure. This vacuum pressure changeswhen a tissue sample is drawn into the inner cannula 17. The vacuumpressure changes again when the tissue is dislodged so that the innercannula is again open to atmospheric pressure. At this point, the innercannula 17 is clear and free to resume a cutting stroke to exciseanother tissue sample. Thus, the vacuum switch 194 can stroke to itsflow path 194 b to provide fluid pressure to the left side of theoscillating valve 170, causing the valve to stroke to flow path 170 b.

[0112] It can be appreciated from this detail explanation that thehydraulic control system 150 provides a complete system for continuouslyreciprocating the axial motor 22. In addition, the system providesconstant continuous pressure to both the rotary motor 20 and theaspiration line 191, so long as the foot pedal 175 is depressed. Oncethe foot pedal is released, fluid pressure in activation line 180 dropswhich causes the air motor control valve 182 and the aspiration controlvalve 185 to shift to their original or normal positions in which fluidpressure is terminated to those respective components. However, in thepreferred embodiment, pressure is maintained to the reciprocating motor22 because the motor is fed through valve 158, which is connecteddirectly to the fluid source 152.

[0113] The hydraulic control system 150 in the illustrated embodimentincorporates five controllable elements. First, the fluid pressureprovided to activate the reciprocating motor 22 is controlled throughthe regulator 154. In addition, the fluid flow rate to the piston 66 iscontrolled via the adjustable control valve 162. The pressure at whichthe pressure switch 165 is activated is determined by an adjustablereturn spring 166. Likewise, the aspiration pressure vacuum at which thevacuum switch 194 is activated is controlled by an adjustable returnspring 195. Finally the adjustable flow control valve 197 controls thefluid flow from the vacuum switch 194 to the oscillating hydraulic valve170. Each of these adjustable elements controls the rate and duration ofoscillation of the reciprocating motor 22.

[0114] In the preferred embodiment, the pressure switch 165 essentiallyoperates as an “end of stroke” indicators. In other words, when theinner cannula 17 reaches the end of its forward or cutting stroke, itcontacts the cutting board 31. When it contacts the cutting board, thepressure in the cylinder pressure line 161 changes dramatically. It isthis change that causes the pressure switch 165 to change states. Thisstate change causes the oscillating valve 170 to shift valve 158 toterminate fluid pressure to the motor 22, causing it to stop its cuttingstroke and commence its return stroke.

[0115] During this return stroke, the excised tissue sample is graduallydrawn along the aspiration conduit. Also during the return stroke, fluidpressure bleeds from pressure line 161 and pressure switch 165 andultimately from line 168 feeding oscillating valve 170. When this valvestrokes, fluid pressure bleeds from valve 158 allowing the valve toreturn to state 158 a to pressurize the motor 22 for a new cuttingstroke. The operation of each of these hydraulic valves introduces aninherent time delay so that by the time the pressure to thereciprocating motor 22 has been restored the aspiration vacuum haspulled the tissue sample through the entire aspiration conduit and intothe collection trap 55.

[0116] The use of a hydraulically controlled inner cutting cannulaprovides significant advantages over prior tissue cutting devices. Theuse of hydraulics allows most of the operating components to be formedof inexpensive and light-weight non-metallic materials, such asmedical-grade plastics. The hydraulic system of the present inventioneliminates the need for electrical components, which means thatelectrical insulation is unnecessary to protect the patient.

[0117] Perhaps most significantly, the hydraulically controlledreciprocation of the inner cutting cannula provides a cleaner andbetter-controlled cut of biopsy tissue. Since the reciprocating motor 22is fed from a substantially constant source of pressurized fluid, thepressure behind the motor piston 63 remains substantially constantthroughout the cutting stroke. This substantially constant pressureallows the inner cutting cannula to advance through the biopsy tissue ata rate determined by the tissue itself.

[0118] In other words, when the cutting edge 35 encounters harder tissueduring a cutting stroke, the rate of advancement of the motor piston 63and therefor the inner cannula 17 decreases proportionately. Thisfeature allows the cutting edge to slice cleanly through the tissuewithout the risk of simply pushing the tissue. The rotation of thecutting edge can facilitate this slicing action. When the inner cannulaencounters less dense tissue, the constant pressure behind the piston 63allows the cutting edge to advance more quickly through the tissue.

[0119] In alternative embodiment, the rotary motor 20 can consist of anelectric motor, rather than a pneumatic motor. As depicted in FIG. 11,the pressure activation line 180 can be fed to an on-off pressure switch198 that is governed by an adjustable bias spring 199. When theactivation line 180 is pressurized the switch 198 establishes aconnection between an electric reciprocating motor 20 and a battery pack200. Preferably, the battery pack 200 is mounted within the handpiece12, but can instead be wired to an external battery contained within theconsole.

[0120] In the preferred embodiment, the tissue biopsy apparatus 10depicted in FIG. 1 has an overall length of under sixteen inches (16″)and an outer diameter less than one and one quarter inches (1.25″). Theouter cannula and therefore the cutting element 11 have a lengthmeasured from the handpiece 12 of approximately five inches (5″). Theouter cannula preferably has a nominal outer diameter of 0.148″ and anominal inner diameter of 0.136″. The inner cannula most preferably hasa nominal outer diameter of 0.126″ so that it can reciprocate freelywithin the outer cannula without catching on the tissue cutting opening.The inner cannula has a nominal wall thickness of 0.010″, which yields anominal inner lumen diameter of about 0.106.″

[0121] The length of the tissue-receiving opening determines the lengthof biopsy sample extracted per each oscillation of the reciprocatingmotor 22. In one specific embodiment, the opening has a length of about0.7″, which means that a 0.7″ long tissue sample can be extracted witheach cutting cycle. In order to accommodate a large number of thesebiopsy tissue slugs, the collection trap can have a length of about 2.5″and a diameter of about 0.05″. Of course, the interior volume of thecollection trap can vary depending upon the size of each biopsy slug andthe amount of material to be collected. In a specific embodiment, thefilter disposed within the collection trap 55 manufactured byPerformance Systematix, Inc. of Callondoni, Mich.

[0122] In accordance with a specific embodiment, the cutting stroke forthe inner cannula is about 0.905″. The return spring 66 within thereciprocating motor 22 is preferably a conical spring to reduce thecompressed height of the spring, thereby allow a reduction in theoverall length of the hydraulic cylinder 60. In addition, the returnspring 66 can be calibrated so that the return stroke occurs in lessthan about 0.3 seconds. Preferably, the inwardly beveled surface 36 ofcutting edge 35 is oriented at an approximately 30° angle.

[0123] The aspiration pressure vacuum is nominally set at 27 in.Hg.during the cutting stroke. When the cannula is retracted and the outerlumen 27 is open, the vacuum pressure is reduced to 25 in.Hg. Thisaspiration pressure normally allows aspiration of a tissue sample inless than about 1 second and in most cases in about 0.3 second. Inaccordance with a most preferred embodiment, the hydraulic controlsystem 150 preferably is calibrated so that the inner cannula dwells atits retracted position for about 0.3 seconds to allow completeaspiration of the tissue sample. Adjusting the return spring 195 of thevacuum switch 194 can control this dwell rate.

[0124] In a preferred embodiment, the inner cannula 17 can advancethrough the cutting stroke in about two seconds. This stroke speed canbe accomplished with a regulated pressure at source 152 of about 20p.s.i. When the inner cannula reaches the end of its cutting stroke, thepressure can increase at about five p.s.i. per second. Preferably, thereturn spring 166 of the pressure switch 165 is set so that the end ofcutting stroke is sensed within about 0.5 seconds.

[0125] In a modification of the present invention, a tissue biopsyapparatus 300 is configured as depicted in FIGS. 12-24. As with thebiopsy apparatus 10 of the prior figures, the apparatus 300 includes acutting element 302 mounted to a user manipulable handpiece 305. Thehandpiece includes an upper housing 310, and a lower housing 311 (seeFIG. 13). A cannula hub 312 is mounted to the handpiece 305 to supportthe outer cannula 303 of the cutting element 302 in a fashion similar tothat described above. The biopsy apparatus 300 further includes a filtercanister 315 that is removably mounted to the handpiece 305, again in amanner similar to that described above.

[0126] In this embodiment, the biopsy apparatus 300 incorporates asecondary lumen 320 that engages the cannula hub 312. The secondarylumen 320 can be used to supply a quantity of irrigation fluid or ameasured quantity of air to the cutting element, in a manner describedbelow. In the illustrated embodiment, the upper housing 310 preferablyincludes a channel 322 defined along its entire length. The channel isconfigured to receive the secondary lumen 320 therein with the lumenrecessed within the housing so as to not interfere with the ability ofthe surgeon to comfortably grip the biopsy apparatus 300.

[0127] Referring now to FIG. 13, it can be seen that the biopsyapparatus 300 includes a reciprocating motor assembly 330 and a rotarymotor assembly motor 332. Each of these assemblies is constructedsimilar to the like assemblies described above. In the presentembodiment, the reciprocating motor assembly 330 includes a housing 340that is contained within the upper and lower housing 310, 311 thatdefine the handpiece 305.

[0128] The reciprocating motor 334 is similar to the motor describedabove. The motor includes a tube fitting 335 for receiving a hollow tube337 (see FIG. 13). The tube 337 is connected to the hydraulic controlsystem 150 depicted in FIG. 10 to provide an alternating supply ofpressurized air to the reciprocating motor 334 in a manner describedabove.

[0129] As shown in FIGS. 13 and 14, the housing 340 includes a pair ofopposite rails 341, which serve as guides for reciprocation of therotary motor 332. As shown in FIG. 17, the rotary motor 332 includesopposite anti-rotation wings 355 that ride along the rails 341 as themotor 332 is reciprocated, and at the same time resist rotation of therotary motor 332 during its operation. The rotary motor 332 furtherincludes a tube fitting 357 that is arranged to engage a hollow tube 358(see FIG. 13) which, like the tube 337, provides a connection to thehydraulic control system 150.

[0130] The housing 340 forms a Luer fitting 345 at its distal end 342,as illustrated in FIG. 16. The Luer fitting includes a circumferentialrecess 347 and a number of spaced flanges 348. Preferably, four suchflanges spaced at 90° intervals are incorporated into the Luer fitting345. The recess 347 defines an enlarged gap 349 between one pair offlanges. Moreover, a number of retention dimples 350 are defined at thebase of the circumferential recess 347, as depicted in FIGS. 14 and 15.

[0131] The Luer fitting 345 is configured to mate with the cannula hub312. As shown in FIGS. 18-20, the cannula hub 312 includes a number ofLuer wings 370 corresponding in number to the plurality of flanges 348.Each of the wings 370 is configured to fit within the recess the 347between flanges 348. One of the wings 370 includes an enlargement 371that prevents the cannula 312 from being improperly oriented, or morespecifically assures a pre-determined orientation of the tissuereceiving opening of the cannula 312. The enlargement 371 is preferablyconfigured to fit within the enlarged gap 349 of the Luer fitting 345 toinsure an upward orientation of the cutting element 302, as depicted inFIGS. 12 and 13.

[0132] The bottom surface of the cannula hub 312 defines a number ofprotuberances 372. Each of the protuberances is sized to fit within oneof the retention dimples 350 of the Luer fitting 345. Thus, when the hubis pushed into the recess 347 and rotated, each of the protuberances 372engages within a corresponding dimples to hold the cannula hub 312 inplace.

[0133] The cannula hub 312 includes a central bore 376 extending throughthe hub. One portion 377 of the bore is sized to tightly receive theouter cannula 303 of the cutting element 302 as described with respectto outer cannula 15. Preferably, the outer cannula 303 is engaged in asubstantially fluid tight fit. The hub 312 is configured for removableengagement with the Luer fitting 345 of the handpiece 305 so the entirehandpiece can be removed from the hub 312 while the outer cannula 303 isstill in place within the patient.

[0134] When the handpiece is removed, the inner cutting element 304 iswithdrawn from the lumen 306 of the outer cannula, since the innercutting element is connected to the reciprocating motor assembly 334 asdescribed above. Thus, the cannula hub 312 and outer cannula 302 remainat the surgical site to permit introduction of medical treatments orother instruments through the bore 376 and lumen 306. For instance, alocal anaesthetic, drug or treatment material, such as a radioactivepellet, can be introduced in this manner, before, during or after thebiopsy procedure. Moreover, other surgical instruments, such as avisualization scope, can be guided to the biopsy site through the hub312 and cannula 302.

[0135] The cannula hub 312 also includes a tube fitting 375. The Tubefitting 375 mates with the secondary lumen 320 that traverses the outerlength of the handpiece 305. The fitting 375 can be of any suitableconfiguration for providing a fluid-tight engagement between the fittingand a tube.

[0136] Referring to back to FIG. 14, the reciprocating motor assemblymotor housing 340 also includes a proximal end 360 that defines amounting hub 361. The mounting hub is similar to the hub 98 describedabove, and is particularly configured to engage the filter canister 315.As indicated above, the hub and canister interface can be in the form ofa bayonet mount to provide a fluid tight quick release engagement. Theproximal end of the housing 340 defines a circumferential flange 363that is sealed against the ends of the upper and lower housings 310, 311of the handpiece 305. A pair of tube cutouts 365 are formed at theperimeter of the flange 363 to provide a passageway for the hydraulictubes 337 and 358 supplying pressurized fluid to the reciprocating androtary motors.

[0137] In order to accommodate the tubes, as well as to firmly supportthe working components of the handpiece 305, the upper and lowerhousings 310 and 311 can be configured as shown in FIGS. 21-24. In aspecific embodiment, the upper housing 310 includes an interior channel380 that passes substantially along the entire length of the interior ofthe upper housing 310. This interior channel is aligned with one of thetube cutouts 365 in the flange 363 of the housing 340. This interiorchannel can provide a pathway for the tube 358 feeding pressurized fluidto the rotary motor assembly 332. The upper housing 310 further definesa number of interior support walls 382. These walls project into theinterior space and serve as a bulkhead for supporting the variousworking components of the handpiece 305.

[0138] Likewise, the lower housing 311 includes a number of interiorsupport walls 385. In addition, near the proximal end 360, the lowerhousing 311 can include a longitudinal support rib 387 that preferablyis arranged to support the reciprocating motor 334. At least some of theinterior support wall 385 of the lower housing 311 can define tubecutouts 389 to receive the tube 337 feeding pressurized fluid to thereciprocating motor 334.

[0139] In addition, the lower housing 311 can include a number ofmounting holes 395. These mounting holes can be arranged to permitmounting of the tissue biopsy apparatus 300 on an existing biopsy table.In the preferred embodiment of the invention, the biopsy apparatus 300can be mounted on a slideable carriage that can be separately driven toproject the cuffing element 302 into the patient. Support beds of thistype are well known and the mounting feature 395 of the handpiece 305can be specifically configured to accommodate any particular supportbed.

[0140] Preferably, the upper and lower housings 310, 311 includeinterlocking mating edges 397, 398, respectively. In a most preferredembodiment, the edges include press-fit male/female interfaces. When allthe components are assembled within the housing 340, the upper and lowerhousings 310, 311 can be sandwiched about the housing 340, with themating edges 397 and 398 in engagement. In one specific embodiment, theengagement can simply be a removable snap-fit, while in otherembodiments, the engagement can be permanent, such as by the use of anadhesive.

[0141] The tissue biopsy apparatus 300 can be connected to the hydrauliccontrol system 150 described above. Each of the components can operatein a manner similar to that described above. The cannula hub 312provides a fluid interface for the external secondary lumen 320 whichcan be used to introduce a fluid, such as a saline solution, to thesurgical site. In this embodiment, a saline flush can be contained in ahermetically sealed bag, such as bag 400 depicted in FIG. 12.

[0142] In one preferred embodiment, a pinch valve 402 can engage thesecondary lumen, preferably adjacent the saline bag 400. The pinch valvecan be opened at the moment that the cutting blade starts to retractfrom the cutting opening. The pinch valve 402 can be controlled toremain open for a pre-determined period of time, but is preferablyclosed before the cutting blade advances forward to make the next biopsycut. Likewise, the amount of time that the pinch valve remains open toallow the saline flush to enter the cutting element 302 can becalibrated based upon a pre-determined volume of fluid desired at thesurgical site. In some procedures, the pinch valve 402 remains open for1-2 seconds, although in certain applications, a shorter time in therange of 0.5 seconds may be preferred. The valve operation can becalibrated to achieve a specific fluid volume, such as about 1 cc ofsaline.

[0143] In one particular embodiment, the hydraulic control system 150depicted in FIG. 10 can be modified to incorporate a fluid linebranching from the line 192. As described above, the line 192 ispressurized when the reciprocating motor starts its return stroke.Pressure in the branch fluid line can be used to open the pinch valve402, while a drop in pressure can operate to close the valve.Alternatively, the pinch valve can be electrically controlled, again inresponse to fluid pressure in line 192 which signals the beginning ofthe motor return stroke. The closure of the pinch valve 402 can bedictated by a drop in pressure in line 192 or by an increase in pressurein line 161, which arises as the reciprocating motor begins its cuttingstroke. It is understood that while a pinch valve is described, otheron-off type fluid valves can be utilized to control the timing of fluidflow through the lumen 320 and cannula hub 312.

[0144] Several benefits arise by providing the saline flush. One primarybenefit is that the saline flush can keep the cutting element clean ofblood and tissue that might otherwise clot or jam the advancement of theinner cutting member. A further benefit is that the saline canfacilitate drawing tissue into the cutting opening during the cuttingcycle. Moreover, the saline flush can help propel the excised tissuetoward the collection canister.

[0145] As an alternative, or an adjunct, the secondary lumen 320 can beused to introduce a puff of air into the cutting element 302. The puffof air, like the saline can be used to keep the interior channel of thecutting element clean. If properly pressurized, the introduction of aircan prevent blood from flowing into the cutting element 302 as thecutting member and excise tissue sample is retracted. Thus, the salinebag 400 can be replaced with a source of pressurized air. In certainapplications, the air source can provide air pressurized to 3-5 p.s.i.g.As with the saline flush, the secondary lumen 320 can be closed as thecutting blade advances to remove a tissue sample, and opened as theblade starts to retract. The pressurized air will pass around theoutside of the inner cutting blade toward the opening at the end of thecutting element 302. The pressure of this puff of air can be calibratedas necessary to counteract the blood pressure at the surgical site andkeep the blood from flowing into the cutting element 302.

[0146] The tissue biopsy apparatus 10 or 300 described above providessignificant advantages over prior biopsy devices. One significantbenefit is that the apparatus of the present invention is completelyclosed. This feature means that no fluid, such as blood, can escape orleak from the biopsy apparatus 10 or 300. In prior devices, the eachextracted tissue sample is drawn into a removable opening that is opento the atmosphere. The present invention does not include any componentthat is open to the atmosphere, with the exception of the secondarylumen 320 which is controllably open to atmosphere to keep theaspiration passageway open and clean. The present invention provides asystem for repeatably and precisely withdrawing uniformly sized biopsysamples. With each stroke of the cutting blade, a uniformly dimensionbiopsy sample is withdrawn and pulled into the collection canister atthe proximal end of the apparatus. Thus, the biopsy apparatus 10 and 300of the present invention can readily remove an entire lesion or regionof suspect tissue. This is a significant improvement over prior devicesthat are only capable of extracting a limited quantity of tissue forbiopsy evaluation only.

[0147] While the invention has been illustrated and described in detailin the drawings and foregoing description, the same is to be consideredas illustrative and not restrictive in character. It should beunderstood that only the preferred embodiments have been shown anddescribed and that all changes and modifications that come within thespirit of the invention are desired to be protected.

EXAMPLES Example 1

[0148] Eighteen trial biopsies were performed upon patients afterobtaining informed consent and preparing the patients according tostandard biopsy procedures. In each case, biopsies were performedaccording to the following procedure. The patient was positioned on herback on the surgical table, and the lesion was located using ultrasound.A small incision was made in the breast. While viewing the lesion usingultrasound, an early embodiment of the present invention was insertedinto the breast with the tissue receiving opening adjacent the lesion.The cutter was engaged to sample and/or remove the lesion. The lesionsvaried in size from 6-22 mm. The surgeon's comments are provided inTable 1. TABLE 1 Surgeon's Comments Regarding the Use of EarlyEmbodiments of the Present Biopsy Device Trial Number Surgeon's Comments1 Went very well, lesion took approximately 50 seconds to go away 2Large fatty breast, very difficult to get needle to mass; eventuallysuccessfully removed 3 Successfully removed without problems 4 Went verywell; lesion gone in 4-5 cores 5 Two lesions attempted (1) lesion easilyremoved, (2) inner cutter was riding up and catching the opening 6 Onlytook 4-5 cores to disappear 7 Started getting good cores, then stoppedcutting due to secondary electrical break 8 Lesion appeared to betotally gone, cores were up to 25 mm in length 9 Only got 4-5 goodcores, then stopped cutting due to inner cutter riding up 10 No problems11 No problems at all 12 Lesion was easily palpable but very mobilewhich made access difficult. Used tactile sensation to manipulate tumorinto aperture which worked very well; very good cores; Took 4.5 minutesbut many of the cores were fatty as a lot of the time I was missing thelesion before realizing that palpitation was better 13 Took 3-4 coresthen quit cutting, blade was dulled, probably due to deflection of tipdownward 14 Went very well, no problems 15 Went well, no problems 16Went well, no problems 17 Went very well 18 Went very well, the suctiontubing collapsed, need stronger tubing; filter did fill up requiringstopping to empty, might need larger filter

[0149] Table 1 illustrates the success of the present invention in itsearly stage of development. A majority of the trials, trials 1-6,8,1-12, and 14-18, resulted in a successful removal of the lesion withlittle to no problems. Lesions were removed quickly and, in some cases,only a few cores were required (see trials 1, 4, and 6). In trial number8 it was noted that the cores were up to 25 mm in length.

[0150] In some trials, the surgeon experienced difficulties removing thelesion because the inner cutting blade would ride up and catch on thetissue receiving opening (see trials 5, and 9). However, this problemhas been resolved in the present invention by integrating a crimp in theouter cannula. The crimp forms a dimple that protrudes from the innersurface of the cannula and into the outer lumen. As the inner cannulapasses the dimple, the dimple forces the inner cannula away from thetissue-receiving opening and prevents the inner cannula from riding upinto the opening. In a further embodiment, the cutting edge of the innercannula is inwardly beveled. This inwardly beveled surface also helpseliminate risk of catching by guiding the inner cannula back into thehollow outer cannula. In addition, to prevent the deflection of the tipdownward, as noted in trial 13, a stiffening element is provided on theouter cannula opposite the tissue-receiving opening.

Example 2

[0151] Surgeons performing biopsies using the device of this inventionand a device having the features of U.S. Pat. No. 5,526,822 to Burbankprovided feedback as to the efficiency of each device. The surgeons'input was used to calculate the amount of time and the number of strokesnecessary to remove a lesion. Table 2 compares the amount of time andthe number of strokes necessary to remove comparable lesions using eachdevice. TABLE 2 Comparison of Removal Times and Number of Strokes of thePresent Biopsy Device with the Prior Art Device Present Biopsy DevicePrior Art Removal Times (sec) Lesion Diameter 10 80 500 13 135 845 16205 1280 No. of Strokes Lesion Diameter 10 16 25 13 27 42 16 41 64

[0152] This data demonstrates that the present tissue biopsy apparatusconsistently removes a lesion with fewer strokes and in less time thanthe prior cutter. The present tissue biopsy device performs 80% fasterthan the prior cutter, which ultimately results in reduced trauma to thetissue.

CONCLUSION

[0153] The biopsy devices of this invention reliably, quickly andefficiently sample and remove lesions in tissue.

What is claimed:
 1. A tissue cutting device comprising: an elongatedhandpiece defining an elongated channel on an outer surface of saidhandpiece; a cannula hub mounted to said handpiece and having a fluidport; a tube connected at one end to said fluid port and having anopposite end connectable to a fluid source, said tube disposed withinsaid elongated channel and sized to be recessed within said channelrelative to said outer surface an outer cannula supported at a proximalend by said cannula hub and defining a tissue-receiving opening adjacenta distal end thereof, and a lumen between said proximal and distal endsin fluid communication with said fluid port of said cannula hub; and aninner cutting member slidably disposed within said lumen of said outercannula and defining a cutting edge at said distal end operable to severtissue projecting through said tissue-receiving opening.
 2. The tissuecutting device of claim 1, further comprising a fluid source connectedto said opposite end of said tube, said fluid source including: acontainer holding a supply of a fluid; and a valve between saidcontainer and said fluid port and operable to control the flow of fluidfrom said container through said tube.
 3. The tissue cutting device ofclaim 2, wherein said valve is a pinch valve engaged about said tube. 4.A method for performing a tissue biopsy at a sample site within apatient comprising the steps of: introducing an outer cannula into thepatient with a tissue receiving opening adjacent the sample site;providing a medical treatment through the outer cannula at the samplesite; connecting the outer cannula to a tissue biopsy handpiece having amotor-driven tissue cutting cannula with the tissue cutting cannulaextending into the outer cannula; operating the tissue biopsy handpieceto excise tissue through the tissue receiving opening; and storing theexcised tissue for subsequent examination.
 5. A tissue cutting devicefor removing tissue from a patient comprising: an outer cannulaconfigured for introduction into the patient and defining atissue-receiving opening adjacent a distal end thereof; an inner cannulaslidably disposed within said outer cannula and defining a lumen from anopen distal end to an open opposite end, said inner cannula furtherdefining a cutting edge at said open distal end operable to sever tissueprojecting through said tissue-receiving opening; a motor assemblyoperably coupled to said inner cannula to rotate and reciprocate saidinner cannula within said outer cannula; a vacuum source fluidly coupledto said inner cannula for generating a vacuum in said lumen of saidinner cannula to draw severed tissue therethrough; and a tissuecollection chamber interposed between said vacuum source and said openopposite end of said inner cannula to receive severed tissue drawn intosaid chamber by the vacuum.
 6. The tissue cutting device of claim 5,wherein said tissue collection chamber includes a filter permittingpassage of fluid therethrough while retaining the severed tissue withinsaid chamber.
 7. A tissue cutting device comprising: an outer cannuladefining a tissue-receiving opening adjacent a distal end thereof; aninner cannula slidably disposed within said outer cannula and defining alumen from an open distal end to an open opposite proximal end, saidinner cannula defining a cutting edge at said open distal end operableto sever tissue projecting through said tissue-receiving opening; arotary motor operably coupled to said inner cannula to rotate said innercannula within said outer cannula; a reciprocating motor operablycoupled to said rotary motor to translate said rotary motor and therebytranslate said inner cannula within said outer cannula while said innercannula rotates; and a handpiece supporting said rotary motor and saidreciprocating motor, said handpiece including a pair of opposite rails,wherein said rotary motor includes a pair of opposite outwardlyprojecting wings configured to be slidably supported on said oppositerails to resist rotation of said rotary motor while permitting saidrotary motor to translate relative to said rails.